Apparatus for circulating water



May 5, 1953 H. B. DAVIDSON APPARATUS FOR CIRCULATING WATER Filed Sept.17, 1949 Patented May 5, 1953 *UNI E S S PATENT OFFICE 5.63753; CIRCULAIING Her l pevi ar Lees-Y le as ira n S t e 94?? Se a s9- 1. 6

.5 e s. (o1. es' z ise) This invention relates to an apparatus forpumping water from a subterranean" source and returning water to thesubterranean source after it has been used for absorbing heat from ordelivering heat to a heat exchanger.

Well water is used extensively for absorbing the heat in condensers,heat exchangers or other equipment and it has been common practice tosimply discharge the water into the sewer after it has'served suchpurposes;

Where a number of wells are constructed and operated in a given area totake out water at a rate higher than the natural recharge rate thestatic water level will be lowered gradually, thereby increasing thepump n h d nd some cases eventually exhausting the supply. To forestallsuch conditions, laws have been enacted in s me localities'to enforcereturn of the water to the source, thereby preserving the static waterlevel as well as the upply.-

' Under e cessive use the temperature or the sou ce Wate w ll hechanged. However, th r are: new ear-round combination heating andcooling plants operating on a subterranean source of water; that raisethe temperature of the water during the cooling or summer season andlower t ur n t e h at g r winterseason. with the net result of verylittle change in the year-round average. Illustrative, if water weretaken out of. the ground, during. the Summer, at 60 degrees and re ed t70 degrees and during the winter months taken out at 60 degrees. andreturn d a 5 de re s. very little, if any. act a chan e in su te raneanWater temperaturewou d re ult Durin re ent years, s me communities haveenacted a ewer tax. wh ch. is. based upon the. water bill. and ollec eal n with the same: Als u h a sewer; tax has been based upon the numberor gallons dumped into the sewer by well water users who are required toput water meterson wells owned and operated by them. This sewer tax. isa heavy burden on large water. users suc a dairies and distilleries.This tax s'into thousands. of dollars per year. in'some as 7 above ta edconditions have developed a. demand. forfapparatus adaptable for,supplying. and discharging water for, heat. exchangers under.

private ow ership. To'supply. this demand and.

provide apparatus for operation wherein the,

source 'ofwater and the temperature. thereof can be safe uarded whileproviding for long.

periods of. operatic h minimum of, service are "the principal objects ofm invention.

Other objects of this invention, somewhat more specifically stated, areto provide the fol.- lowing:

(1) To reduce the cost of supplying water.

.(2) .To reduce the cost of disposing or water.

(3) To provide apparatus and a flexible meth: 0d of operation forpumping and disposing of the water, after changing the temperaturethere-r of, wherein only a portion of the equipment need be employed tomaintain successful operation.

(4.) To provide means for protecting the source of water and theapparatus against clog ging incident to the precipitation of solids.

In installations where water is pumped from one alluvial well to a heatexchanger and then discharged into another similar well the variousminerals that were in solution are converted into solids, of courseinyvarying, degrees, and carried in suspension while the water is underactive circulation and finally deposited. Under. less active circulationor when "in a quiescent state the particles lodge in the Well screen andin the alluyium, thus eventia'lly the well becomes clogged in part orentirely. The time required for this clogging to take place will dependon the nature of the well, the chemical constituents of the water and towhat extent it has'been heated or aerated.

To disclose this invention a specific embodie ment is illustrated in theaccompanying draw--v ing wherein:

The sole figure in the drawing is an elevation, principally in sectionto indicate diagrammatical-v ly. two deep wellsv projecting into waterbearing sand, gravel and earth and each well equipped ing's; 9A and 9B,well screens, [0A and H13, mo-

tors in and 1B for operating, conventional impeller "within bowls [5,53. Conduits ll, MB to which are, attached impeller bowls I5, I53,

respectively, anol'in, which are mounted impeller.

shafts 'according'to conventional practice are to he understood as .pumpcolumns. 8A,8l 3 are bases, respectively, for. motors IA, IB andalsol'serve assca orthe cas n s. The, static waterlevel, indicated as [2, may.be

anywhere frornaiew feet from" the surface to several hundred feet deepdepending on location and local conditions. Wells of this type arecommon in the river valleys and in numerous flat land sections where thebed rock is not close to the surface. Return systems can also besuccessfully operated in areas of this kind where there is no water ontop of the rock. In such cases the wells are often not cased norscreened and depend on the flow of water or return flow of undergroundstreams or porous layers. Also, under these conditions it is desirableto backwash (reverse flow) periodically to remove accumulated solids.The apparatus described previously and the operation thereof would bethe same except for construction of the well.

In operation, the pump associated with well WI draws water from the areaadjacent screen IOA and forces it through pump column I I, pressureconduit 6, and conduit MA. With valve IA closed, valve I6A open, andvalve IGB closed, water is supplied to condenser or cooling coil I4 and,by means of return conduit 5 (with valve I'IA closed and valve I'IBopen) the discharge is forced into casing 913 of well W2. Likewise, touse well W2 in connection with the cooling coil, motor IA of WI isstopped and all the valves are closed except I6B and HA, thus, the flowof water is through screen I BE, impeller bowl I5B, central conduit IIB,pressure conduit 6, conduit I4A, the cooling coil, conduits MB and 5into casing 9A. These conduits will be referred to hereinafter,sometimes, as pipe lines." Gauge I3B will indicate the freedom withwhich the water is flowing into the return well or when back pressurestarts to build up from clogging, thus the operator will know by thepressure indicated on the gauge when it is time to backwash (reverseflow) the well to remove the accumulatedmatter which is clogging thescreen, sand, gravel, or other subterranean structure.

"To backwash (reverse flow) and clean out well W2, it is only necessaryto open the valve I5B' in blow off line TB, and close valve IBB, thenstart pump IB, thus reversing the direction of flow of water throughscreen IOB, which will dislodge and flush out the accumulated mineralsor other matter. Thus, reversing the flow of water in this well cleansnot only the screen and well itself but also the sand and gravel orother formation around the well screen. By watching the discharge fromthe blow off and observing when it clears up the operator will know howlong to backwash (reverse flow) which is usually only a matter of a fewminutes, then he can close the valve in blow off line 'IB, open thevalves I BE and I IA, close valves ISA and HE and pump from the secondwell W2, through the coil or condenser I4, and return the water into theother well WI. Obviously, the reverse flow in well W2 will furtherloosen up the formation and if the well spacing is liberal, the tendencyto heat the underground water will be minimized. The plant can thenoperate until well WI needs cleaning when the procedure, describedabove, is reversed.

Likewise, when pressure builds up in well WI, gauge ISA will indicatethe condition whereupon valve ISA is closed, valve I5A opened, motor IAstarted to efiect the backwash (reverse flow) and discharge water ladenwith accumulated solids from IA. When effected, the system may be setfor normal operation.

It will be noted that the pressure sides of the two pumps in my watercirculating system are directly connected through the pressure conduit 6while the well casings are directly connected through the return conduit5, valves being provided in these conduits so that water can be pumpedselectively from either well into the pressure conduit, through the heatexchanger, into the return conduit and then into the casing of thesecond well.

It will be seen that the two wells will be used alternately forproduction and return but it may also be advisable, under someconditions, to use one well continuously for production and have theother for return, simply stopping the production well occasionally and"blowing off the return well; therefore, the system may also be composedof a production and return well instead of an alternating system, inwhich case, obviously, some of the pipes and valves shown on drawingcould be eliminated.

It is to be understood that a preferred embodiment of my invention hasbeen disclosed and that alterations and modifications can be madeWithout departing from the spirit of this invention as defined in thefollowing claims.

I claim:

1. A water circulating system comprising in combination a pair of wellswhich are spaced apart and connected to a source of water, said wellscomprising well casings and pump columns, a pair ofindependently-operated pumps having a pressure side and a suction sideand'adapted to pump water from said wells, a pressure conduit connectingthe pressure sides of said pumps; a return conduit connecting the Wellcasings of said wells, a heat exchanger connected between the pressureconduit and the return conduit and adapted to receive water from thepressure conduit and to discharge it into said return conduit after heatexchange, and valve means in said conduits so connected that water canbe pumped selectively from the pump column of one of said wells, throughthe pressure conduit, through the heat exchanger and through the returnconduit to the well casing of the other well.

2. A water circulating system comprising in combination a pair ofspaced-apart wells each provided with well casings leading to a commonsource of water, with pump columns and independently operated pumpshaving suction sides and pressure sides, a return conduit directlyconnecting the well casings of the two wells, a pressure conduitdirectly connecting the pressure sides of the two pumps, a heatexchanger connected between the pressure conduit and the return conduitadapted to receive water from the pressure conduit and to discharge itinto said return conduit, and valves positioned in the pressure conduitand in the return conduit in order selectively to direct the waterpumped from either one of said wells through the heat exchanger and theninto the well casing of the other well. I

3. A water circulating system comprisin in combination a pair of wellsprovided with well casings, having screens at their lower ends, and withpump columns, said wells being spaced apart but connected to a commonsource of water located in an alluvial deposit, a heat exchanger, meansincluding valve-controlled conduits con-. necting the inlet of saidexchanger to said pump columns and other valve-controlled conduitsconnecting the outlet of said exchanger to said well casings for pumpingwater selectively from the p p column of either of said wells throughsaid heat exchanger and then into the well casing of:

5 the second well, and valve-controlled blow-off lines connected to saidpump columns, respectively, so that water can be pumped from the pumpcolumn of either of said wells directly through a blow-01f line therebyto clean the well screen of said well from accumulated solids.

4. A Water circulating system according to claim 1 wherein said valvemeans includes two cut-off valves connected in said pressure conduitbetween the inlet of said heat exchanger and said pump columnsrespectively, and including two valve-controlled blow-off linesconnected to said pressure conduit at locations between said cut-oilvalves and said pump columns, whereby solids which accumulate in eachwell may be flushed through said blow-off lines without passing throughsaid heat exchanger.

5. A water circulating system according to claim 4 wherein each of saidwell casings is provioled at its lower end with a screen.

HAROLD B. DAVIDSON.

